The invention relates to a blocking device having two blocking elements located displaceably relative to one another, and to a gear-drive unit containing such a blocking device as well as to a method for producing a gear-drive unit, as generically defined by the preambles to the independent claims.
With European Patent Disclosure EP 1 320 175 A2, a drive and/or braking mechanism has become known in which a brake unit is located inside a housing that surrounds an electric motor. The brake unit has a brake disk and a brake body, which can be pressed against one another electromagnetically by friction-locking. The brake body is connected to the housing of the electric motor in a manner that is both axially fixed and fixed against relative rotation, while the brake disk is located axially displaceably on the rotatably supported armature shaft of the electric motor.
A braking device designed in this way has the disadvantage that upon installation of the drive unit, many tolerances must be compensated for, since upon assembly the brake body is pre-installed directly on the housing and the brake disk is pre-installed on the armature shaft and only after that are they put together and adjusted relative to one another. Moreover, the friction lock between the two brake disks is very vulnerable to wear and such external factors as dirt, carbon dust, grease and jarring, which is why in EP 1 320 175 A2 the housing of the electric motor must also be closed off in a water-tight, air-tight and dust-tight way.